[CI] switch from Travis to Github Action (#132)

* Use Github Actions for CI

Changes:

* remove appveyor (and also windows 32bit)
* leave travis for coverage report
* caching artifacts dir in CI

.github/workflows/UnitTest.yml

@@ -0,0 +1,47 @@
+name: Unit test
+
+on:
+  create:
+    tags:
+  push:
+    branches:
+      - master
+  pull_request:
+  schedule:
+    - cron: '20 00 1 * *'
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        julia-version: ['1.0', '1', 'nightly']
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+
+    steps:
+      - uses: actions/checkout@2
+      - name: "Set up Julia"
+        uses: julia-actions/setup-julia@v1
+        with:
+          version: ${{ matrix.julia-version }}
+
+      - name: Cache artifacts
+        uses: actions/cache@v1
+        env:
+          cache-name: cache-artifacts
+        with:
+          path: ~/.julia/artifacts 
+          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
+          restore-keys: |
+            ${{ runner.os }}-test-${{ env.cache-name }}-
+            ${{ runner.os }}-test-
+            ${{ runner.os }}-
+
+      - name: "Unit Test"
+        uses: julia-actions/julia-runtest@master
+
+      - uses: julia-actions/julia-processcoverage@v1
+      - uses: codecov/codecov-action@v1
+        with:
+          file: lcov.info

.gitignore

@@ -1,3 +1,4 @@
 *.jl.cov
 *.jl.*.cov
 *.jl.mem
+/Manifest.toml

README.md

@@ -1,6 +1,6 @@
 # ColorVectorSpace
 
-[![Build Status](https://travis-ci.org/JuliaGraphics/ColorVectorSpace.jl.svg?branch=master)](https://travis-ci.org/JuliaGraphics/ColorVectorSpace.jl)
+[![Build Status](https://github.com/JuliaGraphics/ColorVectorSpace.jl/workflows/Unit%20test/badge.svg)](https://github.com/JuliaGraphics/ColorVectorSpace.jl/actions)
 [![codecov.io](http://codecov.io/github/JuliaGraphics/ColorVectorSpace.jl/coverage.svg?branch=master)](http://codecov.io/github/JuliaGraphics/ColorVectorSpace.jl?branch=master)
 
 This package is an add-on to [ColorTypes](https://github.com/JuliaGraphics/ColorTypes.jl), and provides fast